Hydrangea plant named ‘H217903’

ABSTRACT

A new and distinct cultivar of Hydrangea plant named ‘H217903’, characterized by its compact, upright and rounded plant habit; vigorous growth habit and moderate growth rate; freely branching habit with strong, thick and sturdy stems; early and freely flowering habit; lacecap-type inflorescences with numerous double-type sterile flowers that are bright red purple in color; and good postproduction longevity.

Botanical designation: Hydrangea macrophylla.

Cultivar denomination: ‘H217903’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Hydrangea plant, botanically known as Hydrangea macrophylla, commercially referred to as a lacecap-type Hydrangea and hereinafter referred to by the name ‘H217903’.

The new Hydrangea plant is a product of a planned breeding program conducted by the Inventor in De Kwakel, The Netherlands and Glandorf, Germany. The objective of the breeding program was to create new compact and freely-branching Hydrangea plants with strong sturdy stems, large inflorescences with numerous double-type sterile flowers, attractive sterile flower color and good postproduction longevity.

The new Hydrangea plant originated from a cross-pollination made by the Inventor in March, 2012 in De Kwakel, The Netherlands, of a proprietary selection of Hydrangea macrophylla identified as code number 10-0169-002 not patented, as the female, or seed, parent with a proprietary selection of Hydrangea macrophylla identified as code number 10-0170-025, not patented, as the male, or pollen, parent. The new Hydrangea plant was discovered and selected by the Inventor as a single flowering plant from within the progeny of the stated cross-pollination in a controlled greenhouse environment in Glandorf, Germany in March, 2013.

Asexual reproduction of the new Hydrangea plant by vegetative tip cuttings in a controlled environment in De Kwakel, The Netherlands since April, 2014 has shown that the unique features of this new Hydrangea plant are stable and reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

Plants of the new Hydrangea have not been observed under all possible combinations of environmental conditions and cultural practices. The phenotype may vary somewhat with variations in environmental conditions such as temperature and light intensity without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined to be the unique characteristics of ‘H217903’. These characteristics in combination distinguish ‘H217903’ as a new and distinct Hydrangea plant:

-   -   1. Compact, upright and flat-top plant habit.     -   2. Vigorous growth habit and moderate growth rate.     -   3. Freely branching habit with strong, thick and sturdy stems.     -   4. Early and freely flowering habit.     -   5. Lacecap-type inflorescences with numerous double-type sterile         flowers that are bright red purple in color.     -   6. Good postproduction longevity.

Plants of the new Hydrangea can be compared to plants of the female and male parent selections. Plants of the new Hydrangea differ primarily from plants of the female and male parent selections in sterile flower form as sterile flowers of plants of the new Hydrangea are double-types with several whorls of sepals whereas sterile flowers of plants of the female and male parent selections are single-types with a single whorl of sepals.

Plants of the new Hydrangea can be compared to plants of the Hydrangea macrophylla ‘H216906’, disclosed in U.S. Plant patent application Ser. No. 15/731,672. In side-by-side comparisons, plants of the new Hydrangea differ primarily from plants of ‘H216906’ in the following characteristics:

-   -   1. Plants of the new Hydrangea have lacecap inflorescences         whereas plants of ‘H216906’ have mophead inflorescences.     -   2. Inflorescences of plants of the new Hydrangea are shorter and         flatter than and not as globular as inflorescences of plants of         ‘H216906’.     -   3. Plants of the new Hydrangea have larger sterile flowers with         larger sepals of plants of ‘H216906’.     -   4. Plants of the new Hydrangea have darker red purple-colored         sterile flower sepals than plants of ‘H216906’.     -   5. Plants of the new Hydrangea and ‘H216906’ differ in reaction         to aluminum sulfate treatment as sterile flower sepals of plants         of the new Hydrangea treated with aluminum sulfate become violet         blue in color whereas sterile flower sepals of plants of         ‘H216906’ treated with aluminum sulfate become light purple in         color.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying colored photographs illustrate the unique appearance of the new Hydrangea plant showing the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Colors in the photographs may differ from the color values cited in the detailed botanical description which accurately describe the colors of the new Hydrangea plant.

The photograph on the first sheet is a side perspective view of a typical flowering plant of ‘H217903’.

The photograph on the second sheet is a top perspective view of a typical flowering plant of ‘H217903’.

The photograph on the third sheet is a close-up view of a typical developing inflorescence of ‘H217903’ that has not been “blued”, that is, treated with aluminum sulfate.

The photograph on the fourth sheet is a close-up view of a typical developing inflorescence of a plant of ‘H217903’ that has been “blued”.

DETAILED BOTANICAL DESCRIPTION

Plants used in the aforementioned photographs and in the following description were grown during the late spring and early summer in 13-cm containers in a glass-covered greenhouse in De Kwakel, The Netherlands and under cultural practices typical of commercial Hydrangea production. During the production of the plants, day and night temperatures averaged 17° C. Plants of the new Hydrangea were one year old when the photographs and description were taken. Plants of the new Hydrangea can be successfully treated with aluminum sulfate to “blue” the inflorescences. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2015 Edition, except where general terms of ordinary dictionary significance are used.

-   Botanical description: Hydrangea macrophylla ‘H217903’. -   Parentage:     -   -   Female, or seed, parent.—Proprietary selection of Hydrangea             macrophylla identified as code number 10-0169-002, not             patented.         -   Male, or pollen, parent.—Proprietary selection of Hydrangea             macrophylla identified as code number 10-0170-025, not             patented. -   Propagation:     -   -   Type cutting.—By vegetative tip cuttings.         -   Time to initiate roots, summer.—About two weeks at             temperatures about 23° C.         -   Time to initiate roots, winter.—About 18 days at             temperatures about 20° C.         -   Time to produce a rooted young plant, summer.—About four             weeks at temperatures about 23° C.         -   Time to produce a rooted young plant, winter.—About five             weeks at temperatures about 20° C.         -   Root description.—Thick; typically whitish brown in color,             actual color of the roots is dependent on substrate             composition, water quality, fertilizer type and formulation,             substrate temperature and physiological age of roots.         -   Rooting habit.—Freely branching; dense. -   Plant description:     -   -   Plant and growth habit.—Compact, upright and flat-top plant             habit; strong and sturdy stems; moderate growth rate and             vigorous growth habit.         -   Plant height.—About 32 cm.         -   Plant diameter or area of spread.—About 45 cm to 50 cm. -   Lateral branch description:     -   -   Branching habit.—Freely branching habit; when pinched, about             six to eight lateral branches develop per plant.         -   Length.—About 25 cm.         -   Diameter.—About 4 mm to 5 mm.         -   Internode length.—About 3 cm to 6 cm.         -   Texture.—Smooth, glabrous; fully developed, woody.         -   Aspect.—Upright to about 20° from vertical.         -   Strength.—Strong, sturdy.         -   Color.—When developing: Close to 144C; at internodes, close             to 187B; lenticels, close to 187A. Developed: Close to 144A;             at the internodes, close to 187B; when woody, close to 177C;             lenticels, close to 187A. -   Leaf description:     -   -   Arrangement.—Opposite, simple.         -   Length.—About 11 cm.         -   Width.—About 6 cm to 8 cm.         -   Shape.—Ovate.         -   Apex.—Acute.         -   Base.—Obtuse.         -   Margin.—Serrulate.         -   Texture, upper surface.—Smooth to rugose, glabrous.         -   Texture, lower surface.—Rugose, glabrous.         -   Venation pattern.—Pinnate.         -   Color.—Developing and fully developed leaves, upper surface:             Close to 147A; venation, close to 145B. Developing and fully             developed leaves, lower surface: Close to 137D; venation,             close to 145C.         -   Petioles.—Length: About 2 cm to 2.5 cm. Diameter: About 3 mm             to 4 mm. Texture, upper and lower surfaces: Smooth,             glabrous. Color, upper and lower surfaces: Close to 145B. -   Flower description:     -   -   Flower type and habit.—Double-type sterile flowers arranged             on lacecap-type terminal panicles; panicles flattened in             shape; flowers face upright to outwardly depending on their             position in the inflorescence; no fertile flowers have been             observed on plants of the new Hydrangea to date.         -   Fragrance.—None detected.         -   Natural flowering season.—Early flowering habit, plants             begin flowering about 10 to 15 months after planting;             flowering begins in the early summer and is continuous             throughout the summer in Northern Europe.         -   Flower longevity.—Sterile flowers last about four months on             the plant, sterile flowers persistent.         -   Quantity of flowers.—Freely flowering habit; outer whorl of             flowers, about 20 to 30; total per inflorescence, about 140             to 160 sterile flowers per panicle; to date, no fertile             flowers have been observed on plants of the new Hydrangea.         -   Panicle height.—About 4 cm.         -   Panicle diameter.—About 15 cm to 20 cm.         -   Sterile flower buds.—Length: About 3 mm. Diameter: About             3 mm. Shape: Rounded. Color: Close to 144B.         -   Sterile flower diameter.—About 5 cm by 8 cm.         -   Sterile flower depth (height).—About 1.5 cm to 2.5 cm.         -   Petals, sterile flowers.—Petal development has not been             observed on plants of the new Hydrangea to date.         -   Sepals, sterile flowers.—Quantity and arrangement: About 13             to 14 in about three whorls. Length, outer whorl: About 3.5             cm to 4 cm. Width, outer whorl: About 3.5 cm to 4 cm.             Length, inner whorls: About 1.5 cm. Width, inner whorls:             About 1 cm. Shape: Ovate. Apex: Obtuse. Base: Obtuse.             Margin: Entire. Texture, upper and lower surfaces: Smooth,             glabrous. Color: When opening, upper and lower surfaces:             Close to 145C. Fully opened, upper surface: Outer sepals,             close to 1457C; when “blued”, close to 94B; colors do not             change with development. Fully opened, lower surface: Close             to 65A; when “blued”, close to N82D; colors do not change             with development.         -   Pedicels, sterile flowers.—Length: About 3 cm to 4 cm.             Diameter: About 2 mm to 3 mm. Strength: Strong. Aspect:             Erect to about 45° from vertical. Texture: Smooth, glabrous.             Color: Close to 65B.         -   Reproductive organs.—To date, reproductive organ development             has not been observed on sterile flowers of plants of the             new Hydrangea; all reproductive organs are “transformed”             into inner whorls of sepals.         -   Fruits and seeds.—Fruit and seed development has not been             observed on plants of the new Hydrangea to date. -   Pathogen & pest resistance: To date, under commercial production     conditions, plants of the new Hydrangea have not been observed to be     resistant to pathogens and pests common to Hydrangea plants. -   Temperature tolerance: Plants of the new Hydrangea have been shown     to be tolerant to temperatures ranging from about 3° C. to about 38°     C. 

It is claimed:
 1. A new and distinct Hydrangea plant named ‘H217903’ as illustrated and described. 